/*
 * Copyright (c) 2003, 2013, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 */

package java.net;

/**
 * This class represents a proxy setting, typically a type (http, socks) and
 * a socket address.
 * A {@code Proxy} is an immutable object.
 *
 * @author Yingxian Wang
 * @author Jean-Christophe Collet
 * @see java.net.ProxySelector
 * @since 1.5
 */
public class Proxy {

  /**
   * Represents the proxy type.
   *
   * @since 1.5
   */
  public enum Type {
    /**
     * Represents a direct connection, or the absence of a proxy.
     */
    DIRECT,
    /**
     * Represents proxy for high level protocols such as HTTP or FTP.
     */
    HTTP,
    /**
     * Represents a SOCKS (V4 or V5) proxy.
     */
    SOCKS
  }

  ;

  private Type type;
  private SocketAddress sa;

  /**
   * A proxy setting that represents a {@code DIRECT} connection,
   * basically telling the protocol handler not to use any proxying.
   * Used, for instance, to create sockets bypassing any other global
   * proxy settings (like SOCKS):
   * <P>
   * {@code Socket s = new Socket(Proxy.NO_PROXY);}
   */
  public final static Proxy NO_PROXY = new Proxy();

  // Creates the proxy that represents a {@code DIRECT} connection.
  private Proxy() {
    type = Type.DIRECT;
    sa = null;
  }

  /**
   * Creates an entry representing a PROXY connection.
   * Certain combinations are illegal. For instance, for types Http, and
   * Socks, a SocketAddress <b>must</b> be provided.
   * <P>
   * Use the {@code Proxy.NO_PROXY} constant
   * for representing a direct connection.
   *
   * @param type the {@code Type} of the proxy
   * @param sa the {@code SocketAddress} for that proxy
   * @throws IllegalArgumentException when the type and the address are incompatible
   */
  public Proxy(Type type, SocketAddress sa) {
    if ((type == Type.DIRECT) || !(sa instanceof InetSocketAddress)) {
      throw new IllegalArgumentException("type " + type + " is not compatible with address " + sa);
    }
    this.type = type;
    this.sa = sa;
  }

  /**
   * Returns the proxy type.
   *
   * @return a Type representing the proxy type
   */
  public Type type() {
    return type;
  }

  /**
   * Returns the socket address of the proxy, or
   * {@code null} if its a direct connection.
   *
   * @return a {@code SocketAddress} representing the socket end point of the proxy
   */
  public SocketAddress address() {
    return sa;
  }

  /**
   * Constructs a string representation of this Proxy.
   * This String is constructed by calling toString() on its type
   * and concatenating " @ " and the toString() result from its address
   * if its type is not {@code DIRECT}.
   *
   * @return a string representation of this object.
   */
  public String toString() {
    if (type() == Type.DIRECT) {
      return "DIRECT";
    }
    return type() + " @ " + address();
  }

  /**
   * Compares this object against the specified object.
   * The result is {@code true} if and only if the argument is
   * not {@code null} and it represents the same proxy as
   * this object.
   * <p>
   * Two instances of {@code Proxy} represent the same
   * address if both the SocketAddresses and type are equal.
   *
   * @param obj the object to compare against.
   * @return {@code true} if the objects are the same; {@code false} otherwise.
   * @see java.net.InetSocketAddress#equals(java.lang.Object)
   */
  public final boolean equals(Object obj) {
    if (obj == null || !(obj instanceof Proxy)) {
      return false;
    }
    Proxy p = (Proxy) obj;
    if (p.type() == type()) {
      if (address() == null) {
        return (p.address() == null);
      } else {
        return address().equals(p.address());
      }
    }
    return false;
  }

  /**
   * Returns a hashcode for this Proxy.
   *
   * @return a hash code value for this Proxy.
   */
  public final int hashCode() {
    if (address() == null) {
      return type().hashCode();
    }
    return type().hashCode() + address().hashCode();
  }
}
